1. Field of the Invention
This invention generally relates to integrated circuit (IC) fabrication and, more particularly, to a nanotip capacitor and a method for fabricating the same.
2. Description of the Related Art
Recently, the fabrication of nanowires has been explored, due to its potential importance as a building block in nano, microelectromechanical (MEM), and nanoelectromechanical NEM device applications. For example, researchers associated with Charles Lieber of Harvard University have reported the synthesis of a variety of semiconductor nanowires made from materials such as silicon (Si), Si-germanium (SiGe), InP, and GaN, for use in building nano-computing system. Other groups have also reported using templates structures to grow metallic nanowires made of materials such as Ni, NiSi, Au, and Pt. Metallic nanowires can be used as interconnections and the sharp tips of the nanowire make them effective for field emission purpose. For example, ZnO nanowires are potentially useful as a light emission element. However, metallic nanowires are fragile, and it is difficult to efficiently fabricate electrical devices from nanowires.
Nanowires can potentially be used in the fabrication of capacitors. There are several methods known to increase the capacitance per unit area of a conventional capacitor electrode. Some methods are: increasing the dielectric constant of the insulator between the electrodes, roughening the electrodes to increase their effective surface area, and using arogel-based supercapacitors. Arogel-based supercapacitors have very large energy storage capability, but the fabrication process is not compatible with conventional silicon (Si) integrated circuit (IC) processes. Additionally, three-dimensional electrodes can be formed, alternately spacing top and bottom electrode fins. However, these structures are difficult to efficiently fabricate.
It would be advantageous if capacitors could be fabricated with nanotip electrodes, forming cost-effective three-dimensional capacitors with ultra high capacitance.
It would be advantageous if the above-mentioned nanotip capacitors could be fabricated in-situ with silicon integrated circuit processes, without additional equipment or chemistry.